DocumentCode :
1330032
Title :
Direct thermal to electrical energy conversion using 9.5/65/35 PLZT ceramics in the ergodic relaxor phase
Author :
Chin, Thomas K. ; Lee, Felix Y. ; McKinley, Ian M. ; Goljahi, Sam ; Lynch, Christopher S. ; Pilon, Laurent
Author_Institution :
Mech. & Aerosp. Eng. Dept., Univ. of California, Los Angeles, CA, USA
Volume :
59
Issue :
11
fYear :
2012
fDate :
11/1/2012 12:00:00 AM
Firstpage :
2373
Lastpage :
2385
Abstract :
This paper reports on direct thermal to electrical energy conversion by performing the Olsen cycle on 9.5/65/35 lead lanthanum zirconate titanate (PLZT). The Olsen cycle consists of two isothermal and two isoelectric field processes in the electric displacement versus electric field diagram. It was performed by alternatively dipping the material in hot and cold dielectric fluid baths under specified electric fields. The effects of applied electric field, sample thickness, electrode material, operating temperature, and cycle frequency on the energy and power densities were investigated. A maximum energy density of 637 ± 20 J/L/cycle was achieved at 0.054 Hz with a 250-μm-thick sample featuring Pt electrodes and coated with a silicone conformal coating. The operating temperatures varied between 3°C and 140°C and the electric field was cycled between 0.2 and 6.0 MV/m. A maximum power density of 55 ± 8 W/L was obtained at 0.125 Hz under the same operating temperatures and electric fields. The dielectric strength of the material, and therefore the energy and power densities generated, increased when the sample thickness decreased from 500 to 250 μm. Furthermore, the electrode material was found to have no significant effect on the energy and power densities for samples subject to the same operating temperatures and electric fields. However, samples with electrode material possessing thermal expansion coefficients similar to that of PLZT were capable of withstanding larger temperature swings. Finally, a fatigue test showed that the power generation gradually degraded when the sample was subject to repeated thermoelectrical loading.
Keywords :
ceramics; electric strength; electrodes; fatigue testing; lanthanum compounds; lead compounds; permittivity; thermal expansion; thermoelectric conversion; Olsen cycle; PLZT; Pt; Pt electrodes; applied electric field effect; cold dielectric fluid bath; cycle frequency effect; dipping; direct thermal-electrical energy conversion; electric displacement; electrode material effect; ergodic relaxor phase; fatigue test; frequency 0.054 Hz; hot dielectric fluid bath; isoelectric field processes; isothermal field processes; lead lanthanum zirconate titanate ceramics; material dielectric strength; maximum energy density; maximum power density; operating temperature effect; operating temperatures; power generation; repeated thermoelectrical loading; sample thickness effect; silicone conformal coating; size 250 mum; temperature 3 degC to 140 degC; thermal expansion coefficients; Density measurement; Electric fields; Electrodes; Isothermal processes; Materials; Power system measurements; Temperature measurement;
fLanguage :
English
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
Publisher :
ieee
ISSN :
0885-3010
Type :
jour
DOI :
10.1109/TUFFC.2012.2470
Filename :
6343264
Link To Document :
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